The deaths occurred in New Mexico, Colorado, Texas, Kansas, Nebraska, Maryland, Missouri and Oklahoma, the BBC reports. It states that there are three more deaths that could be related to the outbreak.

Records from the Centers for Disease Control and Prevention show it has become the deadliest outbreak of a food-borne illness since 1998, when 21 people died from eating tainted hot dogs.

The outbreak was first reported September 12 and symptoms can take four weeks or more to appear.

"That long incubation period is a real problem," Dr Robert Tauxe of the CDC said, as reported by BBC. "People who ate a contaminated food two weeks ago or even a week ago could still be falling sick weeks later."